Valve control mechanism



A. L. PARKER VALVE CONTROL MECHANISM July 20, 1937.

Filed May 4, 1956 2 Sheets-Sheet l July20,1937. ARKEg 2,087,356

VALVE CONTROL MECHANI SM Filed May 4, 1936 2 Sheets-Sheet 2 Patented July 20, 1937 UNITED STATES PATENT OFFICE 2,087,356 VALVE CONTROL MECHANISM Arthur L. Parker, Cleveland, Ohio Application May 4, 1936, Serial No. 77,843

8 Claims.

variations of'pressure are necessary. For ex-.

ample, in a vacuum controlled braking system, the amountof pressure applied to the brakes depends upon the difierence in pressure between opposite ends of the brake cylinder and, in order to get the desired braking effect, it is necessary to vary the degree of vacuum in one end of the cylinder, while the other end is either at atmospheric pressure or constantly connected to the source of vacuum.

With the above conditions in mind, it is the primary object of the present invention to provide an improved valve control mechanism adapted to be' interposed in a pipe line, which is connected at one end to a source of vacuum, said mechanism being operable at will to establish the desired differential between opposite ends of the line.

Another object of the invention is to provide a variable stop, which may be quickly and easily manipulated to vary the maximum'differential to be established. k

The invention will be particularly described in connection with the accompanying drawings, which illustrate the preferred form thereof and in which,--

Figure l is a side elevation of the invention.

Figure 2 is a plan view thereof.

Figure 3 is a horizontal section taken on a plane immediately above the valve control cam.

Figure 4 is a central longitudinal sectional view.

Figure 5 is a detail view of the variable stop.

Figure 6 is a perspective view of .the vacuum valve disk.

As illustrated in the drawings, my improved control mechanism comprises a body In adapted to be connected to a pipe I l and a cap l2 adapted to be connected to a pipe l3. A plate I4 with gaskets I5 is interposed between the ,cap I2 and the body H], which are'secured together by screws IE or the like. The cap l2 has a central orifice [1 leading into the pipe l3 and the plate I4 has a central orifice, l8, about which is a washer l9, seated between the plate and the cap.

A vacuum valve disk 20 is formed with arms 2 l', by which it is guided for reciprocation within the cap [2, and is adapted to beclosed against the washer 19 by the pressure of a coil spring 22, which seats against an internal annular shoulder 23. An adjusting cam member 24 is located centrally of the body l0 and a coil spring 25, acting between the cam member 24 and the vacuum valve disk 20, urges the latter toward open position in opposition to the action of the spring 22.

The plate [4 is formed with a series of atmospheric ports 26 leading from an annular chamber 21 in the cap l2, which is defined by upturned arms 28. The chamber 21 is preferably lined by a sieve or air strainer 29. The ports 26 are adapted to be closed by an annular air inlet valve 38 under pressure from coil springs 3|, which are seated against the adjusting cam member 24.

In order to adjust the cam member 24 down wardly to increase the tension of the springs 25 and 3t, a hub 32 is secured or integrally connected to a spindle 33, which is rotatably mounted in the wall of the body in and provided with washers 34 and 35 above and below the same. The spindle is also formed with a non-circular head 36, to which an arm 31 is suitably secured.

The hub 32 is provided with cam balls 38, which are mounted in recesses 39 and are adapted to travel over the cam surfaces 40 of the member 24 as the arm 31 is moved to the right or left. To prevent rotation of the member 24, it' is splined at 4| to the body l0.

As illustrated in Figure 2, the arm 31 is movable within a range of approximately 90 and its position is indicated by a pointer 42 associated with a scale 43 inscribed upon a plate 44, which is secured to the body It]. The movement of the arm 31 is limited in one 'direction by the boss 45 and in the other direction by the shoulder 46.

Under certain conditions, as hereinafter explained, it is desirable to shorten the range of movement of the arm 31. For this purpose, the hand grip 41 is carried by a spindle 48, which is rotatably mounted in the arm 31. The inner end of the spindle 48 carries a cam 49 which 'is' adapted to engage the stop 45 or 46 in limiting the position of the arm 31. The rotation of the cam'49 and spindle 48 in the arm 31 is limited by the engagement of a pin 50 on the handle 41 with a lug 5| von the end of the'arm'. With the cam 49 in the full line position shown in Figurefi, the range of the arm 31 is shortened in onedirection and with the cam in the dotted line position, the range is shortened in the opposite direction.

In the operation of the invention, assuming that the pipe I3 is connected to the source of vacuum, if the arm 31 is positioned so that the balls 38 are at the low points of the cam surfaces 48, the spring 25 will be under minimum comopen the valve 20. At the same time, the springs 3| are under minimum compression and permit atmospheric air to flow past them into the pipe ll until the latter is substantially at atmospheric pressure. If'the pipe H is connected to one end of the brake cylinder, therefore, while the otherend of the cylinder is connected to the source of vacuum, it is obvious that maximum pressure will be applied to the brakes. is moved to the right until the balls-38 are-on the high points of the cam surfaces 40, as shown in Figure 4, the springs 3| will be under maxi-' 31, the brakes, of course, will beapplied" with difierent pressures as desired by the operator.

If the valve control mechanism is used in a system, in which one end of the brake cylinder is open to the atmosphere, instead of being connected to the source of vacuum, the effect on the brakes if of course reversed. That is, maximum i applied to the brakes.

is applied to a trailer, it is not generally adpressure on the springs 25 and 3| will set the brakes and minimum pressure on these springs will release the brakes, so that the calibration on the plate 44 would in that case be reversed.

In the application of the invention to either type of brake cylinder, it is desirable at times to lessen the amount of maximum pressure to-be Forexample, if the system visable to apply the full braking power when the trailer has a light load. In that case, the

rotatable hand grip with the cam- 49 provides. a

very convenient and readily manipulated means to stop the throw of the arm 31 before it reaches maximum braking position. However, if the cam.

is set in this way for a light load and the operator for any reason wishes to use the full braking power, he may by a simple turn of the wrist reset the cam so that it will permit the maximum throw of the arm 31. While I have shown and described in detail the present preferred form of the invention, it is to be understood that this is merely for the purpose of illustration and that the invention includes such modifications as may fall within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is: I

1. In a device of the character described, the combination with a vacuum valve adaptedto be exposed on one side to a source of vacuum, and a spring tending to close the valve in opposition to the pull of the vacuum, of tin-"atmospheric -'valve, means normally. holding the atmospheric valve closed by pressure, and means to relieve such pressure to admit atmospheric air to the opposite side of the vacuum valve and at the same time to increase the eflectiveness of the vacuum valve closing spring.

2'. In a'device or the character described, the

combination with a vacuum valve adapted to be I exposed on one side to a source of vacuum, and a spring tending to close the valve in opposition to the pull of the vacuum, oi a second spring tend- Now, if the arm 31 thereon.

ing to open the valve, an atmospheric valve,

means normally holding the atmospheric valve closed by pressure, and means to relieve such pressure to admit atmospheric air to the'side of the vacuum valve away from the sourceof vacuum and at the same time to relieve the tension of the second spring.

' 3. In a device of the character described, the

combination with a vacuum valve adapted to be exposed on one side to a source of vacuum, and a spring tending to close the valve in opposition to the pull of the vacuum, or a. eha'mber 'on the opposite side of the valve with-air ports leading thereto, a valve for the air ports, a second spring tending to open-the vacuum valve, springs tending to close the air valve, and means for simultaneously relieving the tensionof the second and -last mentioned springs. I I ."4. In a device of the character described, the combination with "a vacuum valve adapted to be exposed on one side to a source of vacuum, and

a spring tending-to close the valve in opposition to the pull of the vacuum, of a chamber on the opposite side of the valve with air ports leading thereto, a valveforthe air ports, a second spring "tending to open the vacuum valve, springs tending to close the air valve, and-cam means movable .through different stages to cause simultaneous and similar variations in thejtension oi the second and last mentioned springs.

5. In a device oifthe character described, the combination with a vacuum valve adapted to be exposed on one side to a source of vacuum, and a spring tending to close the valve in opposition -to the pull of the vacuum, of a chamber on the opposite side of the valve with air ports leading thereto, a valve for the air ports, springs tending to close the air. valve, andmeans i'or simultaneously opening the vacuum valve and increasing the tension of the air valve springs.

' 6. In a device of the character described, the

combination with a valve and spring means tend- 'ing to hold the same closed against a diii'erential of pressure on opposite sides thereof, of means including an arm movable about'a pivot to pro- 'gressively vary the total effect of said spring means, stops to limit the pivotal movement oi said arm, a hand grip on said arm, and a cam secured to said grip' and engageablewith said stops, said hand grip being movable to'adiust the cam and thereby adjust the range of movement of saidarm.

'I. The combination with a chamber having a port, a valve adapted to cover said port, spring means, tending to close said valve, another spring means tending to open it. said chamber having an atmospheric port, a valve adapted to cover the atmospheric port, a third spring means tending to close the atmospheric valve, and means for simultaneously increasing or decreasing the tension of the second and third spring means.

8. The combination with a chamber having a port, a valve adapted to cover said port, spring means tending to close said valve, a second spring .means tending to open it, said chamber having an atmospheric port, a valve adapted to cover the atmospheric port, a third spring means tending to close the atmospheric valve, a cam member against which the second and third spring means are seated, and means for moving the cam member a to vary the tension of the spring means seated ARTHUR L. PARKER. 

